4．了解和掌握Linux系统支持的消息通信机制、共享存储区机制。. (1) 消息的创建、发送和接收： 使用系统调用msgget( )、msgsed( )、msgrev及msgcrl( )，编写消息的发送和接收程序（消息长度为1KB）； (2) 共享存储区的创建、附接和断接： 使用系统调用shmget( )、shmat( )、shmcrl( )，编写一个与上述功能相同的程序。-4. Understanding and support Linux messaging mechanism, shared memory mechanism. . (1) the creation of news, send and receive : the use of system calls msgget (), msgsed (), and msgrev msgcrl (), the preparation of the sender and receiver (news length of the 1KB); (2) shared storage area creation, and attached disconnect : use of system calls shmget (), shmat (), shmcrl (), a preparation of the above functions with the same procedure.